The invention concerns a nail plate, intended specially for the joining of wooden components, consisting of a sheet-metal plate with several rows columns of nails formed by tongue-shaped punch-outs.
A nail plate of this type is known from EPC patent application No. 85 89 0234.9. In the nail plate therein described, individual punch-outs from which the nails are formed run parallel to the longitudinal sides of a rhomboidal plate, while base points of the nails are parallel to the joint between the connected beams.
The alignment of nails parallel to the joint has proven to be a disadvantage with this design, since it results in an orientation approximately in line with the grain of the wood. A splitting effect exerted by each respective row or column of nails increases, the more closely the row of nails is aligned with the wood grain. With increasing or oscillating load and at maximum load, documented cases have shown the danger of nails loosening, thereby reducing the bearing strength of the plate.
Another disadvantage of this prior art nail plate is its relatively high manufacturing cost. The reason is that when the plate during manufacture is stripped along the sides parallel to the joint, the diagonal sides require a trimming cut which unavoidably leads to waste. If, to prevent this waste, one wishes to run the plates through the punching equipment in the direction of the diagonal, lateral edges, the punching tool stampers must be staggered, which requires costly modification of the punching tool.
A final disadvantage of the described nail plate is that it has no nails in its central area. A considerable portion of the nail plate thus fails to contribute to its joining power.